Revelers came with umbrellas and dressed for the cold, especially those who arrived early for a coveted spot along the parade route.
Savannah's St. Patrick's Day festival is the nation's second-largest.
Between 200,000 and 500,000 people attend.
David Bright of Nashua, N.H., couldn't tell that this year's estimate was on the low end of that spectrum, owing mostly to it being mid-week.
"This is my first St. Patrick's Day and I didn't expect so many people, but this crowd is huge and there's people from everywhere," Bright said. "The crowd's really, really good."
Savannah native Howard Spiva said, few people were counting.
"They like to have fun and party and celebrate the holiday and see their friends and just have a good time," Spiva said.
Jade Irvin said, she prefers the family-friendly parade to the night-time revelry, much of it beer-swilled for the young adult crowd.
"I think the floats, the beads and bands, the kids like that a lot. It's tradition. They did it so many years and the rain won't stop it," Irvin said. "My favorite thing about the parade are the Shriners. And the soldiers are my favorite."
Long-time parade-watchers said this year's crowd was thinner than most, mostly because fewer people can take off from work on a Wednesday.
Light rain also threatened the parade.
Businesses count on this, the city's largest tourist draw, to boost sales.
Savannah's early Irish immigrants started the parade in 1824.
Contributors: Victoria Phetmisy contributed reporting and photographs.